A Healthcare-Associated Outbreak of HCV Genotype 2a at a Clinic in Seoul

OBJECTIVES: An epidemiological investigation was conducted into a hepatitis C virus (HCV) outbreak at an outpatients clinic in Seoul (2011–2012). The aim of the study was to analyze the scale of infection, identify the source of infection, and route of transmission to prevent hepatitis C transmission in the future. METHODS: A retrospective study of the outpatients and health care workers (n = 7,285) in the target outpatient clinic during 2011–2012 was conducted. The history of the study population infection with hepatitis C, electronic medical records, field visits, and health care worker interviews were examined for the period between March 1(st), 2006 and March 25(th), 2016. The blood samples were collected and tested for anti-HCV antibodies, HCV RNA and HCV gene in 2016. RESULTS: The rate of anti-HCV positive results was 4.4% in the study population. The risk factors associated with an anti-HCV positive result were ≥ 10 clinic visits, and receiving an invasive procedure including a nerve block and a block of the peripheral branch of the spinal nerve (p < 0.05). There were 112 HCV RNA positive cases out of 320 anti-HCV positive test result cases, amongst which 100 cases had the dominant HCV genotype 2a which formed either 1 cluster (n = 56) or 2 clusters (n = 25). This result indicated exposure to a high-association infection source. CONCLUSION: Anti-HCV antibodies and genotypic analysis showed an epidemiological association between the outbreak of HCV and invasive procedures performed (2011–2012) at an outpatients clinic in Seoul.